Who is permitted to enter a public school in PA and what is the protocol they must follow while there? I teach in a public school in Philadelphia and we are trying to find out if there are any...

Who is permitted to enter a public school in PA and what is the protocol they must follow while there?

I teach in a public school in Philadelphia and we are trying to find out if there are any state laws that regulate who is allowed to enter the building. It is school policy that visitors sign in and we are all ok with that, but have a problem with visitors just entering the building and going where ever they please with out signing in. We welcome parents at any time for any length of time, but do not want parents who's rights to their children have been taken away or who, by court order, aren't permitted to see their child. Any ideas?